If the Optura Xi is the MVX3i in PAL land, then I can help as I tested it in the May 2004 issue of Computer Video magazine. Here's what I said about the widescreen mode:

When the camcorder is switched to 16:9 mode, the view widens slightly as more of the 1632 x 1224 chip is being used. And, the image is noticeably distorted - in the viewfinder and sidescreen - as black bars are not used to show the new aspect ratio. Confusingly, when the letters ‘WS’ appear in the display, this denotes that the wind-screen filter is turned on, not wide-screen mode is activated.

Graph-paper-filming tests show that the 16:9 mode uses 20 per cent fewer vertical CCD pixels than in the 4:3 mode but seven per cent more horizontal pixels (see diagram). Canon’s widescreen solution is a small step in the right direction and better than simply losing 25 per cent of the vertical resolution - as was typical just two years ago.

Low-light sensitivity and image stabilisation are unaffected by the switch to widescreen, though the telephoto reach is somewhat reduced and the wide-angle increased slightly. On a side-by-side screen test with a Sony VX2000, the widescreen mode of the MVX3i was just noticeably superior.